Endothelial activation and dysfunction in the pathogenesis of microvascular obstruction in severe malaria--a viable target for therapeutic adjunctive intervention.

influenza Avirus subtype H7N1 antigen to find out its relatedness by means of the HI assay. The H7 antigen reacted with WHO reference antibodies to high titers (HI titer, 320), indicating antigenic similarity with influenza A(H7N9) isolated from China. This revealed the appropriateness of using the H7 virus antigen in the study. All serum samples from the high-risk group and the general population were negative for antibodies against influenza A(H7) strains and influenza A(H5N1). This indicated that there is no population-immunity against influenza A(H7) and influenza A(H5N1), and these viruses did not cause human infections in the study population. Sera from the general population were also negative for antibodies against H9N2 virus. Isolation of influenza A(H9N2) has been reported among poultry from India [6]. It has been shown that 4.7% and 3.8% of poultry workers from Pune were positive by the HI and MN assays, respectively, for antibodies against influenza A(H9N2) [7]. Of the serum samples from highrisk groups in Jamshedpur, 10% (13/ 128) and 5% (6/128) were positive by the HI and MN assays, respectively, for antibodies against influenza A(H9N2). This could be due to circulation of influenza A(H9N2), in poultry in Jamshedpur. This difference in seroprevalence of antibodies against influenza A(H9N2) in Pune and Jamshedpur could be due to differential environmental exposures. The seropositivity against A(H9N2) virus was similar (P > 0.05) in 15–44 and ≥45 years age-groups. The presence of antibodies against influenza A(H9N2) in poultry workers suggests possible transmission of avian influenza viruses from poultry to humans. The present study showed that antibody levels against influenza A(H9N2) were higher than those against other avian influenza viruses, which is in agreement with findings reported by Boni et al. The limitation of this study is that generalization is not possible from the small number of samples studied. In summary, animal-human interface studies, together with enhanced clinical and virologic surveillance in high-risk groups, are required to track possible species transfer of novel avian influenza viruses.